1. Field
The field of the invention is electrolytic recovery of gold from solutions thereof, more particularly to treat carbon eluates and the like to deposit gold-bearing sludges for further refining upon cathode assemblies.
2. Prior Art
Prior art electrowinning, for cathodic production of gold, generally involves the displacement of gold from an aqueous alkaline cyanide solution in an electrolytic cell carrying alternately spaced anodes and cathodes. At proper voltage, deposition of the metal starts upon the cathodes, at a rate depending upon solution parameters, such as conductivity, concentration of ionic species present, temperature and applied cell current. The source of the deposited gold is ionic gold-cyanide within the caustic solution. When parameters are favorable, a fluffy, porous deposit of elemental gold forms upon the cathode, and in some instances then falls upon the cell floor. Other conditions may produce plating upon the cathode, which may be acceptable with some approaches to the electrowinning recovery of gold.
Typically, conditions are brought about within the cell to promote the deposition of gold-bearing sludge upon the cathode structure. The cathode structure typically comprises a cathodic basket which is variously filled with wool of steel or stainless steel, upon the strands of which the gold bearing sludge forms and from which it must be subsequently removed. In prior art devices, the cathode structure must be removed from the electrowinning cell to dislodge and recover the sludge from the steel wool, which is packed into thick layers within baskets, and requires very vigorous washing with water. The baskets surround the cathodes and both are together removed from the electrolytic cell. Strong jets of water are directed perpendicularly to the surface of the cathode plate. Generally, the basket must be disassembled to provide access to the wool for thorough sludge removal. This periodic procedure slows the gold recovery process, and increases its cost.
Therefore, there exists a need for electrowinning cathodes not requiring removal from the cell for dislodging the deposited sludge.